Simulating Cumulus Entrainment: A Resolution Problem, or Conceptual?
Entrainment is the process by which cumulus clouds bring dry air from outside the cloud inward. Entrainment initially favors precipitation formation; eventually, it dilutes the cloud and encourages its demise. A long-standing problem in meteorology has been to reproduce how quickly entrainment dilutes the cloud. Currently, all models fail. It is assumed to be a problem of inadequate spatial resolution, hindering the representation of turbulence at smaller scales. We will test this assumption, incrementally increasing the resolution down to the meter scale if necessary, to quantify what resolution (if any) is successful, as compared with field observations and theoretical predictions.
Blue Waters Annual Reports